Showing posts with label J C Bose and the radio.. Show all posts
Showing posts with label J C Bose and the radio.. Show all posts

Sunday, July 13, 2014

J C Bose and the radio.

This is from Wikepedia  on the work of  J.C.Bose[edit] in relation to  using radio waves. .
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“In November 1894, the Indian physicist, Jagadish Chandra Bose, demonstrated publicly the use of radio waves in Calcutta, but he was not interested in patenting his work.[85] 
Bose ignited gunpowder and rang a bell at a distance using electromagnetic waves,[86] confirming that communication signals can be sent without using wires. He sent and received radio waves over distance but did not commercially exploit this achievement.

Bose demonstrated the ability of the electric rays to travel from the lecture room, and through an intervening room and passage, to a third room 75 feet (23 m) distant from the radiator, thus passing through three solid walls on the way, as well as the body of the chairman (who happened to be the Lieutenant-Governor).
The receiver at this distance still had energy enough to make a contact which set a bell ringing, discharged a pistol, and exploded a miniature mine. To get this result from his small radiator, Bose set up an apparatus which curiously anticipated the lofty 'antennae' of modern wireless telegraphy— a circular metal plate at the top of a pole, 20 feet (6.1 m) high, being put in connection with the radiator and a similar one with the receiving apparatus.[87]
The form of 'Coherer' devised by Professor Bose, and described by him at the end of his paper 'On a new Electro Polariscope' allowed for the sensibility and range to appear to leave little to be desired at the time.[87] In 1896, the Daily Chronicle of England reported on his UHF experiments: "The inventor (J.C. Bose) has transmitted signals to a distance of nearly a mile and herein lies the first and obvious and exceedingly valuable application of this new theoretical marvel."
After Bose's Friday Evening Discourses at the Royal Institution, The Electric Engineer expressed 'surprise that no secret was at any time made as to its construction, so that it has been open to all the world to adopt it for practical and possibly money-making purposes.' Bose was sometimes, and not unnaturally, criticised as unpractical for making no profit from his inventions.[87]

In 1899, Bose announced the development of an "iron-mercury-iron coherer with telephone detector" in a paper presented at the Royal Society, London.[88] Later he received U.S. Patent 755,840, "Detector for electrical disturbances" (1904), for a specific electromagnetic receiver. Bose would continue research and made other contributions to the development of radio.[89]